In recent years, with the popularization of mobile Internet and rapid development of network teaching system, the conventional teaching mode cannot meet user's requirements of teaching mode such as multimedia informatization to facilitate easy playback. During network teaching, excellent teaching resources can be shared on internet, and users can get online access to these resources by recording the teaching process via class recording and broadcasting, the requirement of review after class by students is also met.
As shown in FIG. 1, the existing document 1 (CN10114127 A, publication date 12 Mar. 2008) discloses a network teaching system, which comprises a recorder 100, a processor 200, a first network 300, a second network 350, a server 400, a database 500, and three clients 600, wherein, the recorder 100 mainly includes a camera (not shown in the figure) and a wireless digital microphone (not shown in the figure) for recording the video and audio information of a courseware. The first network 300 is used for transmitting the courseware information to the server 400. On the one hand, the server 400 is used for processing the courseware information further to create courseware data, on the other hand, the server 400 is used for searching and invoking the courseware data in the database 500 and converting the courseware data back into the courseware information. The database 500 is used for storing the courseware data. The second network 350 is used for connecting the client 600 and the server 400. The client 600 is used for facilitating user to inquire courseware information and invoking courseware information.
As shown in FIG. 2, the existing document 2 (CN103067683 A, publication date 24 Apr. 2013) discloses a full automatic recording and broadcasting system for distance teaching, which comprises an video signal collecting module 1 and an audio signal collecting module 2, an automatic recording and broadcasting editing module 3 and a graphic work station 4. The video signal collecting module 1 includes a teacher camera, a student camera and a blackboard writing camera for taking images of teacher, students and blackboard writing respectively, and all of these cameras adopt high speed spherical camera with rotation cradle head. When used, both the video signal collecting module 1 and the audio signal collecting module 2 are connected with the automatic recording and broadcasting editing module 3, and transmits the collected video and audio signals to the automatic recording and broadcasting editing module 3. The automatic recording and broadcasting editing module 3 is connected with the graphic work station 4 and edits the video and audio signals into an audio and video file, then the module transmits the file to the graphic work station 4. The graphic work station 4 compresses and codes the audio and video file for creating a streaming media file. No specially-assigned person is needed for operation and control during the whole process of teaching recording, and the streaming media file can be uploaded to internet.
As shown in FIG. 3, the existing document 3 (CN101043469 A, publication date 26 Sep. 2007) discloses a method for recording personalized multimedia courseware via wireless internet with a mobile phone in a multimedia classroom, which is realized by the information interaction among a courseware service center, a courseware sending center and a mobile phone. The courseware service center has an external IP address and serves for all multimedia classrooms in a teaching building. The courseware sending center collects the screen signal of the teacher's teaching computer, the teacher's video and audio signal, and sends the screen, video and audio data to the service center after digitalization. The mobile phone is connected to the courseware service center via wireless network, and saves one or several streaming media data of them to mobile phone memory card when needed, and saves them as AVI document which can be watched directly on mobile phone or computer after finishing recording.
As shown in FIG. 4, the existing document 4 (CN103646573 A, publication date 19 Mar. 2014) discloses a method for creating special format file for a teaching system in panorama mode, the teaching system includes a panoramic courseware making system which acquires the motion, voice of teacher or interactive student, the class material and the time data corresponding to the time when these data are acquired. The motion includes inserting character or picture, demonstrating experiment process, drawing line, drawing geometric figure, eraser tool or small blackboard tool. The teaching system acquires the instant voice of teacher or interactive student with microphone, acquires the motion of teacher or interactive student on current system interface with mouse, keyboard, tablet or electronic whiteboard at the same time and conducts data analysis to the motion, acquires the time when the motion takes place, the path produced by the motion, the additional data carried by the motion and the data of motion type, and records in chronological order. The motion is divided into handwriting type, media type and data type, all of the handwriting type, media type and data type data include two parts: path part and data part, for the handwriting type motion, the path part completely records physical coordinate sequence of motion path, and the data part is not enabled; for the media motion, the path part records the coordinate of the multimedia file in the courseware, and the data part records the physical address of the multimedia file; for the data type motion, the path part records the coordinate of the data used in the courseware, and the data part writes complete binary data stream of the file.
The existing document 4 puts forward a lot of ideas, however, no specific way is given to realize them, and the document does not disclose separately acquiring and separately accessing various data in a systematic way, in particularly, it does not consider the idea that a unified timestamp is produced by the teaching system and various data streams are managed by unified timestamp and unified label of courseware.
In conclusion, the recording and broadcasting of the multimedia interactive teaching class in existing solutions mainly adopts the follow methods: 1 live recording and broadcasting streaming media on demand from network; 2 recording the class video with the camera hardware equipment on the spot; uploading it to the streaming media server, playing back on demand from network; 3 separately recording video and audio, broadcasting streaming media on demand from network; 4 recording by local screen capture at software client, and uploading it to server after finishing recording, playing back streaming media on demand from network; 5 simulating third party role server to record remotely, that is when starting a class, simulating a system role to achieve the remote recording and video file combination by server, playing back streaming media on demand from network.
In existing solutions, these methods for recording and broadcasting have the following disadvantages: 1 the recording process is cumbersome, some of them need a specially-assigned person to conduct live recording; 2 the video file is huge, file format is required to be transformed many times to reduce the file size at the cost of the courseware quality; 3 there is high requirement for storing system of server; 4 local recording requires high configuration and performance of the client apparatus, the uploading speed is slow, and it is difficult to play back; 5 a lot of server resource is consumed by simulating system role, the requirement of high concurrency network recording of class cannot be met; 6 there is high requirement for cluster performance of streaming media server for playing back on demand; 7 playing back on demand requires high server bandwidth; 8 playing back on demand requires high client's bandwidth (the file is too large); 9 when the video is watched with wireless internet such as 2G/3G/4G, there is heavy stuck, the video cannot be played smoothly, and it consumes high data traffic.
Furthermore, when user downloads the file to a local system and watches it, the file will occupy a large storage space, and the copyright of the teaching resource supplier cannot be protected, resulting in wanton spread of teaching resources. If the file is processed complexly with encryption, it will occupy the resources of network bandwidth and the resources of apparatus processor, affecting user experience.
In addition, the existing commercial software in existing solutions can record every operation on screen and save it as AVI or Microsoft Real Networks data stream format, however, it will also occupy a large storage space, and the data format it supplies is also streaming media.
For this purpose, an effective recording and broadcasting method and system is required to be provided, thus, the recording of function operation of using multimedia whiteboard, speech/speaking voice, communication voice for communication with other user and/or guiding etc. by user during network teaching or online conference is realized, and different data streams are formed respectively, which replaces recording the whole event in streaming media format. In this way, network users can conveniently order video to browse from cloud server or local area network server anytime and anywhere.